I've had Griffith's Gnats hit while repositioning my kayak as well. The fly got pulled under and suddenly I was getting far more hits than when it was floating high & dry.

So, if you're chasing a midge hatch, consider pulling the fly back slowwwwwwwly to you (just crawl the line in with one hand working it in with your fingers).

Just another way to do something the fish aren't expecting (and aren't used to ignoring).